Effects of surface functionalizing and pore structure on dissolved mercury adsorption in gasoline by covalent sulphur-doped templated carbons: Experimental and theoretical insights

Abstract

Mercury pollutants dissolved in gasoline would damage the processing equipment and corrosion the pipeline, which required to be removed. However, the adsorption capacity and selectivity of current adsorbents on mercury pollutants in gasoline make it difficult to meet the demand for green ecological production. In this work, the covalent sulphur-doped templated carbons (TCs) were prepared by the impregnation-pyrolysis (IP) method to remove dissolved ionic mercury (Hg2+) and organic mercury (Hgorg) in gasoline. The maximum adsorption capacities of TCs on Hg2+ and Hgorg were 1904 μg/g and 299 μg/g, respectively. The adsorption selectively of TCs was closely related to their physical and chemical structure. The 50%-TC with more sulphur-containing functional groups (SO and C–S) and micropores showed an adsorption preference for Hg2+. However, 100%-TC dominated by more mesopores coupled with oxygen-containing functional groups (C–O) exhibited better adsorption selectivity for Hgorg. Apart from experimental methods, molecular dynamics (MD) simulation was used to reveal the adsorption mechanism. The results showed that Hg2+ and Hgorg were easily adsorbed by TC samples with pore sizes of 2.03 nm and 2.98 nm, respectively, which was consistent with the adsorption experiment. In the end, the mercury adsorption capacity of TCs decreased by less than 28.5% after five regeneration cycles. The above-discussed results cast a new light on the preparation of highly selective mercury removal adsorbents.